Directions

FOR THE DOUGH: Combine the yeast, sugar, melted butter, egg and milk in the bowl of an electric mixer fitted with a dough hook. Beat on low speed for 1 minute. Add the salt, rye flour and all-purpose flour. Beat at low speed until all of the flour is incorporated, about 1 minute. Then, beat at medium speed until the mixture forms a ball, leaves the sides of the bowl and climbs up the dough hook. Remove the dough from the bowl. Using your hands, form the dough into a smooth ball. Lightly oil a bowl. Place the dough in the bowl and turn it to oil all sides. Cover with plastic wrap and set aside in a warm, draft-free place until it doubles in size, about 1 hour. Set aside.

FOR THE PUMPERNICKEL BREAD: Combine the yeast, water, melted butter, sugar, molasses and chocolate in the bowl of an electric mixer fitted with a dough hook. Beat on low speed for 1 minute. Add the caraway seeds, potatoes, rye flour, wheat flour and cornmeal. Beat at low speed until all of the flour is incorporated, about 1 minute. Then, beat at medium speed until the mixture forms a ball, leaves the sides of the bowl, and climbs up the dough hook. Remove the dough from the bowl. Using your hands, form the dough into a smooth ball. Lightly oil a bowl. Place the dough in the bowl and turn it to oil all sides. Cover with plastic wrap and set aside in a warm, draft-free place until it doubles in size, about 1 hour. Set aside.

Preheat the oven to 350 degrees F.

Remove both of the doughs from their bowls and invert them onto two separate lightly floured surfaces. Pat each dough into a rectangle about 3/4-inch thick. Place the pumpernickel rectangle on top of the rye dough rectangle. Roll up the dough, beginning with the long side and stopping after each full turn to press the edge of the roll firmly into the flat sheet of dough to seal. Press with your fingertips. Tuck and roll so that any seams disappear into the dough and place on a parchment lined baking sheet. With a pastry brush, brush the beaten egg evenly over the bread. Cover with plastic wrap and set aside in a warm, draft-free place until it doubles in size, about 1 hour. Bake until lightly brown, 30 to 35 minutes. Remove from the oven and cool on a rack.